This invention relates to an apparatus for inspecting a pattern shape of a magnetic record medium formed of a patterned medium or a bit patterned medium as an object to be inspected, its stamper or a master as a die of the stumper at high speed and with high sensitivity, and a method thereof.
In recent years, the spread of a mobile device, a digital AV apparatus and so on has been accelerated in addition to a PC and a server, so that the demand toward a hard disc drive (HDD) has been increased, and the quantity of information treated by the HDD has been remarkably increased. On the other hand, miniaturization of the HDD is required to heighten the recording density of the magnetic record media of the HDD. With an increase in recording density of the HDD, vertical magnetic recording system has been developed, but even in the vertical magnetic recording system, with an increase in recording density, the influence due to mutual magnetic interference of adjacent tracks becomes larger, so that it reaches the limitations. Therefore, as a system for recording and reproducing only an object track, development on the discrete track media adapted to physically work a track and magnetically discrete it has been performed. Further, in order to increase the recording density, development on the bit patterned media adapted to record one bit on one magnetic particle has been progressing.
In the discrete track media and the bit patterned media, differently from the conventional magnetic record medium, it is necessary to form the track and the bit pattern. The sizes of the track and the bit pattern are extremely small as much as tens of nanometers, and photo nano-imprint is used as a method of manufacturing a micro-pattern at a low cost.
Then, when variation in size and shape of a pattern, a defect or short-circuit is caused in a pattern formed by the photo nano-imprint technology, the magnetic record medium does not normally operate, and it becomes sometimes defective. Therefore, it is necessary to inspect whether or not a pattern shape is suitable formed. When a defect is found in a stamper serving as a die of the pattern, the defect is copied. Therefore, higher-accuracy inspection is needed. Although SEM (Scanning Electron Microscope) and AFM (Atomic Force Microscope) are cited as a system for inspecting a defect of a micro-pattern, they cannot be applied to inline inspection from a viewpoint of throughput. On the other hand, as a device for detecting a pattern shape defect with high throughput, an optical surface inspection device and an optical critical dimension (OCD) measuring device are cited.
The conventional surface inspection device and OCD measuring device are known in JP-A-2007-304062, JP-T-2007-526444, JP-A-2003-149159 and “Line-profile and critical dimension correlation between a normal incidence optical CD metrology system and SEM”, Proc. SPIE Vol. 4689, 2002, pp 966-976.
In JP-A-2007-304062, it is described that polarized light is applied obliquely to a periodic step pattern on a semiconductor wafer, in reflection, orthogonal polarized light is detected, and the linearity of the periodic step pattern is detected from the intensity of detected light to determine the quality of a focus and the light exposure in exposing a resist pattern.
JP-T-2007-526444 describes an inspection system including an illuminating system, which illuminates a specimen, a condenser configured to condense light scatted from the specimen, a segmented detector, which individually detects different parts of the light to store azimuth and polar angle information on the different parts of the light and generates signals representing the different parts of the light, and a processor, which detects a defect on the specimen from the signal.
JP-A-2003-149159 describes a system for inspecting the surface of a specimen such as a semiconductor wafer, including an illuminating system, which directs a first light beam at a slant incidence angle to the surface of a specimen and directs a second light beam at a substantially vertical angle to the surface of the specimen, a collecting system, which collects at least some of the first and second light beams returning from the surface of the specimen, and a detecting system, which processes the collected parts of the first and second light beams.
“Line-profile and critical dimension correlation between a normal incidence optical CD metrology system and SEM”, Proc. SPIE Vol. 4689, 2002, pp 966-976 describes measurement for CD (Critical Dimension) of a recessed and projecting pattern of a resist film on the poly-Si in the Si substrate by applying scatterometory having the vertical incidence and vertical detection optical system.
JP-A-2007-304062, however, relates to defect detection using linearity detection, and JP-T-2007-526444 and JP-A-2003-149159 relate to defect detection using detection of scattered light, and the inspection of a pattern shape is not taken into consideration.
“Line-profile and critical dimension correlation between a normal incidence optical CD metrology system and SEM”, Proc. SPIE Vol. 4689, 2002, pp 966-976 relates to the technology of measuring CD (Critical Dimension) of a recessed and projecting pattern of a resist film on poly-Si in a Si substrate by applying scatterometory having the vertical incidence and vertical detection optical system, and the inspection of a pattern shape at high speed and with high sensitivity concerning a recessed and projecting pattern of a magnetic record medium such as a patterned medium or a bit patterned medium and a recessed and projecting pattern of a stamper in forming the recessed and projecting pattern of the magnetic record medium by nano-imprint is not taken into consideration.